SmartGPU2-LCD480X320Touch-CommandSet

SMART GPU 2 3.5” TOUCH

Command Set

2.7.2 Play WAV File – 50hex - P ascii

Commands (host)

2 bytes + file name + 1byte(NULL)

1.- 0x41 (hex), A (ascii). *Audio Command.

2.- 0x50 (hex), P (ascii).

3 up to N (file name).

N+1.- 0x00 (hex) NULL ascii.

Responses (device)

2 bytes + 1 byte ACK/NAK

1.- File duration in seconds high byte.

2.- File duration in seconds low byte.

3.- 0x4F (hex), O (ascii) – success ACK or

0x46 (hex), F (ascii) – fail NAK.

Description

When this command is sent and successfully

executed(ACK ‘O’ received) a Wav file stored in the

microSD card will begin playing audio on the

AL(Audio Left channel) and AR(Audio Right channel),

it’s highly recommended to place two 100uF-400uF

capacitors in each output to decouple output

voltage(refer to datasheet for recommended circuitry).

The SmartGPU 2 automatically will read and

sample the audio file(22100Hz, 44100Hz, etc.)

according to the WAV header file. If the file is MONO,

both channels will have the same output, if file is

STEREO, channels will have different output.

The response of this command is very useful as

once the audio file begins playing, user can know the

total file duration in seconds or the time that the

SmartGPU 2 will be playing the audio file.

The file will continue playing until it finish, user can

send any other command meanwhile the audio file is

being played. If this same “Play WAV File” command

is sent while the SmartGPU 2 is already playing

audio, command will be just ignored(NAK) and audio

will continue playing.

The file name must be up to 250 characters. Only

numbers and letters are recommended to name

the file, some special characters are not allowed

and may not work.

Always a NULL character (0x00)hex must follow the

last character of the file name, in order to indicate to

SMART GPU the end of this file name, the name to

receive must not include the .wav extension.